More than 20 states are studying similar proposals, reported the Detroit Free Press, but the Michigan bill would set up a pilot program.

Under the measure, students would agree to pay a fixed percentage of their post-college income for a specified number of years into a special fund to help pay tuition for other students.

The measure calls for a rate of 2 percent for community college students and 4 percent for university students, and each would be required to pay into the fund for five years for each year they attend school under the program.

So, for example, a student who attended the University of Michigan for four years would be asked to pay 4 percent of her income back for 20 years after graduation.

That would work out to $100 a month for graduates who earned $30,000 a year.

“The goal is to remove every financial barrier to high education,” said state Rep. David Knezek (D-Dearborn Heights). “We’ve increasingly place the financial burden of college on the backs of the students. This is a no-interest plan that allows you to pay back as you go and as you can afford it. It takes the monkey off the student’s back.”

The Michigan bill would establish a $2 million fund for a pilot program that involved 200 students, and the state’s treasury department would track the money and verify income.

The interest rates on federal student loans currently range from 3.86 percent for newer loans to 6.8 percent on older loans.

Susan Dynarksi, a University of Michigan professor and expert on higher education finances, said spreading payments out over 20 to 25 years and linking them to income “ensures borrowers against hard times.”

But, she said, borrowers who expect to earn high salaries after college have a disincentive to participate.

“If the future starving artists flood into pay it forward and the future engineers shun it, the program will spiral into insolvency,” she said.

But Dynarski said this flaw could be easily fixed by denominating the debt in dollars, instead of years, so borrowers could stop paying into the system once they’ve paid back their loans.